Several collaborations have been carried out in this project with intramural as well as extramural researchers during the FY 2012-2013 on a wide range of topics. These collaborations have led to several manuscripts that are currently at various stages of publication. Some examples of collaborations are as follows. 1. Study of infant gut microbiome: In addition to the external (chemical) environment, the internal (microbial) environment plays an important role in human health. In recent years there has been considerable interest among researchers to understand the effect of microbiome on various health conditions and diseases, such as obesity, asthma, IBD, depression etc. In collaboration with researchers at the Norwegian Institute of Public Health, in this project we are trying to understand the associations between infant gut microbiome and some early childhood health outcomes. Novel statististical methods are being developed for drawing such associations. 2. Study of DNA methylation in newborns of mothers who smoked during their pregnancy: Maternal smoking during pregnancy is known to be associated with a variety health outcomes in babies. In collaboration with Dr. Stephanie London (EB), we are investigating the effect of maternal smoking during pregnancy on DNA methylation in cord blood obtained from newborns. In Joubert et al. (EHP, 2012) we identified 26 epi-genome wide statistically significant CpGs that mapped onto 10 genes. In addition to AHRR and CYP1A1, we identified several novel genes (e.g. GFI1, MYO1G and RUNX1) that were not previously known to be associated with tobacco smoke. We are now conducting further investigation of these 26 CpG sites to understand the effect of sustained in-utero exposure to smoking throughout pregnancy and epigenetic inheritance of smoking-related modifications.